In many prior art circuits, means and methods have been available to minimize power consumption of series pass devices of series type regulated power supplies. However, such prior art means have not minimized the total power consumption. One example of such means is the bypassing of the series pass device using resistive means during such high line operation. Other examples of series type voltage regulators are found in "Power Supply Circuits", TEKTRONIX, INC., assignee of the present invention.
Means and methods directly related to the present invention (i.e., total power consumption of series type regulated power supplies during high line operation) are shown and described in U.S. Pat. No. 3,060,320, wherein means have been added between the source of primary supply voltage and the series type voltage regulator to reduce voltage variations into the series regulator, hence a reduced consumption of power. Disadvantages of such disclosed prior art are the addition of active components and various reference voltage means required for operation of the active components. Another disadvantage is that all the load current must flow through another active component having current capabilities equivalent to the series pass device capabilities of the series regulated power supply.